/**
 * http://github.com/valums/file-uploader
 * 
 * Multiple file upload component with progress-bar, drag-and-drop. 
 * © 2010 Andrew Valums ( andrew(at)valums.com ) 
 * 
 * Licensed under GNU GPL 2 or later and GNU LGPL 2 or later, see license.txt.
 */

//
// Helper functions
//
var qq = qq || {};

/**
 * Adds all missing properties from second obj to first obj
 */
qq.extend = function(first, second) {
	for ( var prop in second) {
		first[prop] = second[prop];
	}
};

/**
 * Searches for a given element in the array, returns -1 if it is not present.
 * @param {Number} [from] The index at which to begin the search
 */
qq.indexOf = function(arr, elt, from) {
	if (arr.indexOf)
		return arr.indexOf(elt, from);

	from = from || 0;
	var len = arr.length;

	if (from < 0)
		from += len;

	for (; from < len; from++) {
		if (from in arr && arr[from] === elt) {
			return from;
		}
	}
	return -1;
};

qq.getUniqueId = (function() {
	var id = 0;
	return function() {
		return id++;
	};
})();

//
// Events

qq.attach = function(element, type, fn) {
	if (element.addEventListener) {
		element.addEventListener(type, fn, false);
	} else if (element.attachEvent) {
		element.attachEvent('on' + type, fn);
	}
};
qq.detach = function(element, type, fn) {
	if (element.removeEventListener) {
		element.removeEventListener(type, fn, false);
	} else if (element.attachEvent) {
		element.detachEvent('on' + type, fn);
	}
};

qq.preventDefault = function(e) {
	if (e.preventDefault) {
		e.preventDefault();
	} else {
		e.returnValue = false;
	}
};

//
// Node manipulations

/**
 * Insert node a before node b.
 */
qq.insertBefore = function(a, b) {
	b.parentNode.insertBefore(a, b);
};
qq.remove = function(element) {
	element.parentNode.removeChild(element);
};

qq.contains = function(parent, descendant) {
	// compareposition returns false in this case
	if (parent == descendant)
		return true;

	if (parent.contains) {
		return parent.contains(descendant);
	} else {
		return !!(descendant.compareDocumentPosition(parent) & 8);
	}
};

/**
 * Creates and returns element from html string
 * Uses innerHTML to create an element
 */
qq.toElement = (function() {
	var div = document.createElement('div');
	return function(html) {
		div.innerHTML = html;
		var element = div.firstChild;
		div.removeChild(element);
		return element;
	};
})();

//
// Node properties and attributes

/**
 * Sets styles for an element.
 * Fixes opacity in IE6-8.
 */
qq.css = function(element, styles) {
	if (styles.opacity != null) {
		if (typeof element.style.opacity != 'string'
				&& typeof (element.filters) != 'undefined') {
			styles.filter = 'alpha(opacity=' + Math.round(100 * styles.opacity)
					+ ')';
		}
	}
	qq.extend(element.style, styles);
};
qq.hasClass = function(element, name) {
	var re = new RegExp('(^| )' + name + '( |$)');
	return re.test(element.className);
};
qq.addClass = function(element, name) {
	if (!qq.hasClass(element, name)) {
		element.className += ' ' + name;
	}
};
qq.removeClass = function(element, name) {
	var re = new RegExp('(^| )' + name + '( |$)');
	element.className = element.className.replace(re, ' ').replace(
			/^\s+|\s+$/g, "");
};
qq.setText = function(element, text) {
	element.innerText = text;
	element.textContent = text;
};

//
// Selecting elements

qq.children = function(element) {
	var children = [], child = element.firstChild;

	while (child) {
		if (child.nodeType == 1) {
			children.push(child);
		}
		child = child.nextSibling;
	}

	return children;
};

qq.getByClass = function(element, className) {
	if (element.querySelectorAll) {
		return element.querySelectorAll('.' + className);
	}

	var result = [];
	var candidates = element.getElementsByTagName("*");
	var len = candidates.length;

	for ( var i = 0; i < len; i++) {
		if (qq.hasClass(candidates[i], className)) {
			result.push(candidates[i]);
		}
	}
	return result;
};

/**
 * obj2url() takes a json-object as argument and generates
 * a querystring. pretty much like jQuery.param()
 * 
 * how to use:
 *
 *    `qq.obj2url({a:'b',c:'d'},'http://any.url/upload?otherParam=value');`
 *
 * will result in:
 *
 *    `http://any.url/upload?otherParam=value&a=b&c=d`
 *
 * @param  Object JSON-Object
 * @param  String current querystring-part
 * @return String encoded querystring
 */
qq.obj2url = function(obj, temp, prefixDone) {
	var uristrings = [], prefix = '&', add = function(nextObj, i) {
		var nextTemp = temp ? (/\[\]$/.test(temp)) // prevent double-encoding
		? temp : temp + '[' + i + ']' : i;
		if ((nextTemp != 'undefined') && (i != 'undefined')) {
			uristrings
					.push((typeof nextObj === 'object') ? qq.obj2url(nextObj,
							nextTemp, true)
							: (Object.prototype.toString.call(nextObj) === '[object Function]') ? encodeURIComponent(nextTemp)
									+ '=' + encodeURIComponent(nextObj())
									: encodeURIComponent(nextTemp) + '='
											+ encodeURIComponent(nextObj));
		}
	};

	if (!prefixDone && temp) {
		prefix = (/\?/.test(temp)) ? (/\?$/.test(temp)) ? '' : '&' : '?';
		uristrings.push(temp);
		uristrings.push(qq.obj2url(obj));
	} else if ((Object.prototype.toString.call(obj) === '[object Array]')
			&& (typeof obj != 'undefined')) {
		// we wont use a for-in-loop on an array (performance)
		for ( var i = 0, len = obj.length; i < len; ++i) {
			add(obj[i], i);
		}
	} else if ((typeof obj != 'undefined') && (obj !== null)
			&& (typeof obj === "object")) {
		// for anything else but a scalar, we will use for-in-loop
		for ( var i in obj) {
			add(obj[i], i);
		}
	} else {
		uristrings.push(encodeURIComponent(temp) + '='
				+ encodeURIComponent(obj));
	}

	return uristrings.join(prefix).replace(/^&/, '').replace(/%20/g, '+');
};

//
//
// Uploader Classes
//
//

var qq = qq || {};

/**
 * Creates upload button, validates upload, but doesn't create file list or dd. 
 */
qq.FileUploaderBasic = function(o) {
	this._options = {
		// set to true to see the server response
		debug : false,
		action : '/server/upload',
		params : {},
		button : null,
		multiple : true,
		maxConnections : 3,
		// validation        
		allowedExtensions : [],
		sizeLimit : 0,
		minSizeLimit : 0,
		// events
		// return false to cancel submit
		onSubmit : function(id, fileName) {
		},
		onProgress : function(id, fileName, loaded, total) {
		},
		onComplete : function(id, fileName, responseJSON) {
		},
		onCancel : function(id, fileName) {
		},
		// messages                
		messages : {
			typeError : "{file} has invalid extension. Only {extensions} are allowed.",
			sizeError : "{file} is too large, maximum file size is {sizeLimit}.",
			minSizeError : "{file} is too small, minimum file size is {minSizeLimit}.",
			emptyError : "{file} is empty, please select files again without it.",
			onLeave : "The files are being uploaded, if you leave now the upload will be cancelled."
		},
		showMessage : function(message) {
			alert(message);
		}
	};
	qq.extend(this._options, o);

	// number of files being uploaded
	this._filesInProgress = 0;
	this._handler = this._createUploadHandler();

	if (this._options.button) {
		this._button = this._createUploadButton(this._options.button);
	}

	this._preventLeaveInProgress();
};

qq.FileUploaderBasic.prototype = {
	setParams : function(params) {
		this._options.params = params;
	},
	getInProgress : function() {
		return this._filesInProgress;
	},
	_createUploadButton : function(element) {
		var self = this;

		return new qq.UploadButton({
			element : element,
			multiple : this._options.multiple
					&& qq.UploadHandlerXhr.isSupported(),
			onChange : function(input) {
				self._onInputChange(input);
			}
		});
	},
	_createUploadHandler : function() {
		var self = this, handlerClass;

		if (qq.UploadHandlerXhr.isSupported()) {
			handlerClass = 'UploadHandlerXhr';
		} else {
			handlerClass = 'UploadHandlerForm';
		}

		var handler = new qq[handlerClass]({
			debug : this._options.debug,
			action : this._options.action,
			maxConnections : this._options.maxConnections,
			onProgress : function(id, fileName, loaded, total) {
				self._onProgress(id, fileName, loaded, total);
				self._options.onProgress(id, fileName, loaded, total);
			},
			onComplete : function(id, fileName, result) {
				self._onComplete(id, fileName, result);
				self._options.onComplete(id, fileName, result);
			},
			onCancel : function(id, fileName) {
				self._onCancel(id, fileName);
				self._options.onCancel(id, fileName);
			}
		});

		return handler;
	},
	_preventLeaveInProgress : function() {
		var self = this;

		qq.attach(window, 'beforeunload', function(e) {
			if (!self._filesInProgress) {
				return;
			}

			var e = e || window.event;
			// for ie, ff
			e.returnValue = self._options.messages.onLeave;
			// for webkit
			return self._options.messages.onLeave;
		});
	},
	_onSubmit : function(id, fileName) {
		this._filesInProgress++;
	},
	_onProgress : function(id, fileName, loaded, total) {
	},
	_onComplete : function(id, fileName, result) {
		this._filesInProgress--;
		if (result.error) {
			this._options.showMessage(result.error);
		}
	},
	_onCancel : function(id, fileName) {
		this._filesInProgress--;
	},
	_onInputChange : function(input) {
		if (this._handler instanceof qq.UploadHandlerXhr) {
			this._uploadFileList(input.files);
		} else {
			if (this._validateFile(input)) {
				this._uploadFile(input);
			}
		}
		this._button.reset();
	},
	_uploadFileList : function(files) {
		for ( var i = 0; i < files.length; i++) {
			if (!this._validateFile(files[i])) {
				return;
			}
		}

		for ( var i = 0; i < files.length; i++) {
			this._uploadFile(files[i]);
		}
	},
	_uploadFile : function(fileContainer) {
		var id = this._handler.add(fileContainer);
		var fileName = this._handler.getName(id);

		if (this._options.onSubmit(id, fileName) !== false) {
			this._onSubmit(id, fileName);
			this._handler.upload(id, this._options.params);
		}
	},
	_validateFile : function(file) {
		var name, size;

		if (file.value) {
			// it is a file input            
			// get input value and remove path to normalize
			name = file.value.replace(/.*(\/|\\)/, "");
		} else {
			// fix missing properties in Safari
			name = file.fileName != null ? file.fileName : file.name;
			size = file.fileSize != null ? file.fileSize : file.size;
		}

		if (!this._isAllowedExtension(name)) {
			this._error('typeError', name);
			return false;

		} else if (size === 0) {
			this._error('emptyError', name);
			return false;

		} else if (size && this._options.sizeLimit
				&& size > this._options.sizeLimit) {
			this._error('sizeError', name);
			return false;

		} else if (size && size < this._options.minSizeLimit) {
			this._error('minSizeError', name);
			return false;
		}

		return true;
	},
	_error : function(code, fileName) {
		var message = this._options.messages[code];
		function r(name, replacement) {
			message = message.replace(name, replacement);
		}

		r('{file}', this._formatFileName(fileName));
		r('{extensions}', this._options.allowedExtensions.join(', '));
		r('{sizeLimit}', this._formatSize(this._options.sizeLimit));
		r('{minSizeLimit}', this._formatSize(this._options.minSizeLimit));

		this._options.showMessage(message);
	},
	_formatFileName : function(name) {
		if (name.length > 33) {
			name = name.slice(0, 19) + '...' + name.slice(-13);
		}
		return name;
	},
	_isAllowedExtension : function(fileName) {
		var ext = (-1 !== fileName.indexOf('.')) ? fileName
				.replace(/.*[.]/, '').toLowerCase() : '';
		var allowed = this._options.allowedExtensions;

		if (!allowed.length) {
			return true;
		}

		for ( var i = 0; i < allowed.length; i++) {
			if (allowed[i].toLowerCase() == ext) {
				return true;
			}
		}

		return false;
	},
	_formatSize : function(bytes) {
		var i = -1;
		do {
			bytes = bytes / 1024;
			i++;
		} while (bytes > 99);

		return Math.max(bytes, 0.1).toFixed(1)
				+ [ 'kB', 'MB', 'GB', 'TB', 'PB', 'EB' ][i];
	}
};

/**
 * Class that creates upload widget with drag-and-drop and file list
 * @inherits qq.FileUploaderBasic
 */
qq.FileUploader = function(o) {
	// call parent constructor
	qq.FileUploaderBasic.apply(this, arguments);

	// additional options    
	qq
			.extend(
					this._options,
					{
						element : null,
						// if set, will be used instead of qq-upload-list in template
						listElement : null,

						template : '<div class="qq-uploader">'
								+ '<div class="qq-upload-drop-area"><span>Drop files here to upload</span></div>'
								+ '<div class="qq-upload-button">Upload a file</div>'
								+ '<ul class="qq-upload-list"></ul>' + '</div>',

						// template for one item in file list
						fileTemplate : '<li>'
								+ '<span class="qq-upload-file"></span>'
								+ '<span class="qq-upload-spinner"></span>'
								+ '<span class="qq-upload-size"></span>'
								+ '<a class="qq-upload-cancel" href="#">Cancel</a>'
								+ '<span class="qq-upload-failed-text">Failed</span>'
								+ '</li>',

						classes : {
							// used to get elements from templates
							button : 'qq-upload-button',
							drop : 'qq-upload-drop-area',
							dropActive : 'qq-upload-drop-area-active',
							list : 'qq-upload-list',

							file : 'qq-upload-file',
							spinner : 'qq-upload-spinner',
							size : 'qq-upload-size',
							cancel : 'qq-upload-cancel',

							// added to list item when upload completes
							// used in css to hide progress spinner
							success : 'qq-upload-success',
							fail : 'qq-upload-fail'
						}
					});
	// overwrite options with user supplied    
	qq.extend(this._options, o);

	this._element = this._options.element;
	this._element.innerHTML = this._options.template;
	this._listElement = this._options.listElement
			|| this._find(this._element, 'list');

	this._classes = this._options.classes;

	this._button = this
			._createUploadButton(this._find(this._element, 'button'));

	this._bindCancelEvent();
	this._setupDragDrop();
};

// inherit from Basic Uploader
qq.extend(qq.FileUploader.prototype, qq.FileUploaderBasic.prototype);

qq.extend(qq.FileUploader.prototype, {
	/**
	 * Gets one of the elements listed in this._options.classes
	 **/
	_find : function(parent, type) {
		var element = qq.getByClass(parent, this._options.classes[type])[0];
		if (!element) {
			throw new Error('element not found ' + type);
		}

		return element;
	},
	_setupDragDrop : function() {
		var self = this, dropArea = this._find(this._element, 'drop');

		var dz = new qq.UploadDropZone({
			element : dropArea,
			onEnter : function(e) {
				qq.addClass(dropArea, self._classes.dropActive);
				e.stopPropagation();
			},
			onLeave : function(e) {
				e.stopPropagation();
			},
			onLeaveNotDescendants : function(e) {
				qq.removeClass(dropArea, self._classes.dropActive);
			},
			onDrop : function(e) {
				dropArea.style.display = 'none';
				qq.removeClass(dropArea, self._classes.dropActive);
				self._uploadFileList(e.dataTransfer.files);
			}
		});

		dropArea.style.display = 'none';

		qq.attach(document, 'dragenter', function(e) {
			if (!dz._isValidFileDrag(e))
				return;

			dropArea.style.display = 'block';
		});
		qq.attach(document, 'dragleave',
				function(e) {
					if (!dz._isValidFileDrag(e))
						return;

					var relatedTarget = document.elementFromPoint(e.clientX,
							e.clientY);
					// only fire when leaving document out
					if (!relatedTarget || relatedTarget.nodeName == "HTML") {
						dropArea.style.display = 'none';
					}
				});
	},
	_onSubmit : function(id, fileName) {
		qq.FileUploaderBasic.prototype._onSubmit.apply(this, arguments);
		this._addToList(id, fileName);
	},
	_onProgress : function(id, fileName, loaded, total) {
		qq.FileUploaderBasic.prototype._onProgress.apply(this, arguments);

		var item = this._getItemByFileId(id);
		var size = this._find(item, 'size');
		size.style.display = 'inline';

		var text;
		if (loaded != total) {
			text = Math.round(loaded / total * 100) + '% from '
					+ this._formatSize(total);
		} else {
			text = this._formatSize(total);
		}

		qq.setText(size, text);
	},
	_onComplete : function(id, fileName, result) {
		qq.FileUploaderBasic.prototype._onComplete.apply(this, arguments);

		// mark completed
		var item = this._getItemByFileId(id);
		qq.remove(this._find(item, 'cancel'));
		qq.remove(this._find(item, 'spinner'));

		if (result.success) {
			qq.addClass(item, this._classes.success);
		} else {
			qq.addClass(item, this._classes.fail);
		}
	},
	_addToList : function(id, fileName) {
		var item = qq.toElement(this._options.fileTemplate);
		item.qqFileId = id;

		var fileElement = this._find(item, 'file');
		qq.setText(fileElement, this._formatFileName(fileName));
		this._find(item, 'size').style.display = 'none';

		this._listElement.appendChild(item);
	},
	_getItemByFileId : function(id) {
		var item = this._listElement.firstChild;

		// there can't be txt nodes in dynamically created list
		// and we can  use nextSibling
		while (item) {
			if (item.qqFileId == id)
				return item;
			item = item.nextSibling;
		}
	},
	/**
	 * delegate click event for cancel link 
	 **/
	_bindCancelEvent : function() {
		var self = this, list = this._listElement;

		qq.attach(list, 'click', function(e) {
			e = e || window.event;
			var target = e.target || e.srcElement;

			if (qq.hasClass(target, self._classes.cancel)) {
				qq.preventDefault(e);

				var item = target.parentNode;
				self._handler.cancel(item.qqFileId);
				qq.remove(item);
			}
		});
	}
});

qq.UploadDropZone = function(o) {
	this._options = {
		element : null,
		onEnter : function(e) {
		},
		onLeave : function(e) {
		},
		// is not fired when leaving element by hovering descendants   
		onLeaveNotDescendants : function(e) {
		},
		onDrop : function(e) {
		}
	};
	qq.extend(this._options, o);

	this._element = this._options.element;

	this._disableDropOutside();
	this._attachEvents();
};

qq.UploadDropZone.prototype = {
	_disableDropOutside : function(e) {
		// run only once for all instances
		if (!qq.UploadDropZone.dropOutsideDisabled) {

			qq.attach(document, 'dragover', function(e) {
				if (e.dataTransfer) {
					e.dataTransfer.dropEffect = 'none';
					e.preventDefault();
				}
			});

			qq.UploadDropZone.dropOutsideDisabled = true;
		}
	},
	_attachEvents : function() {
		var self = this;

		qq.attach(self._element, 'dragover', function(e) {
			if (!self._isValidFileDrag(e))
				return;

			var effect = e.dataTransfer.effectAllowed;
			if (effect == 'move' || effect == 'linkMove') {
				e.dataTransfer.dropEffect = 'move'; // for FF (only move allowed)    
			} else {
				e.dataTransfer.dropEffect = 'copy'; // for Chrome
			}

			e.stopPropagation();
			e.preventDefault();
		});

		qq.attach(self._element, 'dragenter', function(e) {
			if (!self._isValidFileDrag(e))
				return;

			self._options.onEnter(e);
		});

		qq.attach(self._element, 'dragleave',
				function(e) {
					if (!self._isValidFileDrag(e))
						return;

					self._options.onLeave(e);

					var relatedTarget = document.elementFromPoint(e.clientX,
							e.clientY);
					// do not fire when moving a mouse over a descendant
					if (qq.contains(this, relatedTarget))
						return;

					self._options.onLeaveNotDescendants(e);
				});

		qq.attach(self._element, 'drop', function(e) {
			if (!self._isValidFileDrag(e))
				return;

			e.preventDefault();
			self._options.onDrop(e);
		});
	},
	_isValidFileDrag : function(e) {
		var dt = e.dataTransfer,
		// do not check dt.types.contains in webkit, because it crashes safari 4            
		isWebkit = navigator.userAgent.indexOf("AppleWebKit") > -1;

		// dt.effectAllowed is none in Safari 5
		// dt.types.contains check is for firefox            
		return dt
				&& dt.effectAllowed != 'none'
				&& (dt.files || (!isWebkit && dt.types.contains && dt.types
						.contains('Files')));

	}
};

qq.UploadButton = function(o) {
	this._options = {
		element : null,
		// if set to true adds multiple attribute to file input      
		multiple : false,
		// name attribute of file input
		name : 'file',
		onChange : function(input) {
		},
		hoverClass : 'qq-upload-button-hover',
		focusClass : 'qq-upload-button-focus'
	};

	qq.extend(this._options, o);

	this._element = this._options.element;

	// make button suitable container for input
	qq.css(this._element, {
		position : 'relative',
		overflow : 'hidden',
		// Make sure browse button is in the right side
		// in Internet Explorer
		direction : 'ltr'
	});

	this._input = this._createInput();
};

qq.UploadButton.prototype = {
	/* returns file input element */
	getInput : function() {
		return this._input;
	},
	/* cleans/recreates the file input */
	reset : function() {
		if (this._input.parentNode) {
			qq.remove(this._input);
		}

		qq.removeClass(this._element, this._options.focusClass);
		this._input = this._createInput();
	},
	_createInput : function() {
		var input = document.createElement("input");

		if (this._options.multiple) {
			input.setAttribute("multiple", "multiple");
		}

		input.setAttribute("type", "file");
		input.setAttribute("name", this._options.name);

		qq.css(input, {
			position : 'absolute',
			// in Opera only 'browse' button
			// is clickable and it is located at
			// the right side of the input
			right : 0,
			top : 0,
			fontFamily : 'Arial',
			// 4 persons reported this, the max values that worked for them were 243, 236, 236, 118
			fontSize : '118px',
			margin : 0,
			padding : 0,
			cursor : 'pointer',
			opacity : 0
		});

		this._element.appendChild(input);

		var self = this;
		qq.attach(input, 'change', function() {
			self._options.onChange(input);
		});

		qq.attach(input, 'mouseover', function() {
			qq.addClass(self._element, self._options.hoverClass);
		});
		qq.attach(input, 'mouseout', function() {
			qq.removeClass(self._element, self._options.hoverClass);
		});
		qq.attach(input, 'focus', function() {
			qq.addClass(self._element, self._options.focusClass);
		});
		qq.attach(input, 'blur', function() {
			qq.removeClass(self._element, self._options.focusClass);
		});

		// IE and Opera, unfortunately have 2 tab stops on file input
		// which is unacceptable in our case, disable keyboard access
		if (window.attachEvent) {
			// it is IE or Opera
			input.setAttribute('tabIndex', "-1");
		}

		return input;
	}
};

/**
 * Class for uploading files, uploading itself is handled by child classes
 */
qq.UploadHandlerAbstract = function(o) {
	this._options = {
		debug : false,
		action : '/upload.php',
		// maximum number of concurrent uploads        
		maxConnections : 999,
		onProgress : function(id, fileName, loaded, total) {
		},
		onComplete : function(id, fileName, response) {
		},
		onCancel : function(id, fileName) {
		}
	};
	qq.extend(this._options, o);

	this._queue = [];
	// params for files in queue
	this._params = [];
};
qq.UploadHandlerAbstract.prototype = {
	log : function(str) {
		if (this._options.debug && window.console)
			console.log('[uploader] ' + str);
	},
	/**
	 * Adds file or file input to the queue
	 * @returns id
	 **/
	add : function(file) {
	},
	/**
	 * Sends the file identified by id and additional query params to the server
	 */
	upload : function(id, params) {
		var len = this._queue.push(id);

		var copy = {};
		qq.extend(copy, params);
		this._params[id] = copy;

		// if too many active uploads, wait...
		if (len <= this._options.maxConnections) {
			this._upload(id, this._params[id]);
		}
	},
	/**
	 * Cancels file upload by id
	 */
	cancel : function(id) {
		this._cancel(id);
		this._dequeue(id);
	},
	/**
	 * Cancells all uploads
	 */
	cancelAll : function() {
		for ( var i = 0; i < this._queue.length; i++) {
			this._cancel(this._queue[i]);
		}
		this._queue = [];
	},
	/**
	 * Returns name of the file identified by id
	 */
	getName : function(id) {
	},
	/**
	 * Returns size of the file identified by id
	 */
	getSize : function(id) {
	},
	/**
	 * Returns id of files being uploaded or
	 * waiting for their turn
	 */
	getQueue : function() {
		return this._queue;
	},
	/**
	 * Actual upload method
	 */
	_upload : function(id) {
	},
	/**
	 * Actual cancel method
	 */
	_cancel : function(id) {
	},
	/**
	 * Removes element from queue, starts upload of next
	 */
	_dequeue : function(id) {
		var i = qq.indexOf(this._queue, id);
		this._queue.splice(i, 1);

		var max = this._options.maxConnections;

		if (this._queue.length >= max && i < max) {
			var nextId = this._queue[max - 1];
			this._upload(nextId, this._params[nextId]);
		}
	}
};

/**
 * Class for uploading files using form and iframe
 * @inherits qq.UploadHandlerAbstract
 */
qq.UploadHandlerForm = function(o) {
	qq.UploadHandlerAbstract.apply(this, arguments);

	this._inputs = {};
};
// @inherits qq.UploadHandlerAbstract
qq.extend(qq.UploadHandlerForm.prototype, qq.UploadHandlerAbstract.prototype);

qq
		.extend(
				qq.UploadHandlerForm.prototype,
				{
					add : function(fileInput) {
						fileInput.setAttribute('name', 'qqfile');
						var id = 'qq-upload-handler-iframe' + qq.getUniqueId();

						this._inputs[id] = fileInput;

						// remove file input from DOM
						if (fileInput.parentNode) {
							qq.remove(fileInput);
						}

						return id;
					},
					getName : function(id) {
						// get input value and remove path to normalize
						return this._inputs[id].value.replace(/.*(\/|\\)/, "");
					},
					_cancel : function(id) {
						this._options.onCancel(id, this.getName(id));

						delete this._inputs[id];

						var iframe = document.getElementById(id);
						if (iframe) {
							// to cancel request set src to something else
							// we use src="javascript:false;" because it doesn't
							// trigger ie6 prompt on https
							iframe.setAttribute('src', 'javascript:false;');

							qq.remove(iframe);
						}
					},
					_upload : function(id, params) {
						var input = this._inputs[id];

						if (!input) {
							throw new Error(
									'file with passed id was not added, or already uploaded or cancelled');
						}

						var fileName = this.getName(id);

						var iframe = this._createIframe(id);
						var form = this._createForm(iframe, params);
						form.appendChild(input);

						var self = this;
						this._attachLoadEvent(iframe, function() {
							self.log('iframe loaded');

							var response = self._getIframeContentJSON(iframe);

							self._options.onComplete(id, fileName, response);
							self._dequeue(id);

							delete self._inputs[id];
							// timeout added to fix busy state in FF3.6
							setTimeout(function() {
								qq.remove(iframe);
							}, 1);
						});

						form.submit();
						qq.remove(form);

						return id;
					},
					_attachLoadEvent : function(iframe, callback) {
						qq
								.attach(
										iframe,
										'load',
										function() {
											// when we remove iframe from dom
											// the request stops, but in IE load
											// event fires
											if (!iframe.parentNode) {
												return;
											}

											// fixing Opera 10.53
											if (iframe.contentDocument
													&& iframe.contentDocument.body
													&& iframe.contentDocument.body.innerHTML == "false") {
												// In Opera event is fired second time
												// when body.innerHTML changed from false
												// to server response approx. after 1 sec
												// when we upload file with iframe
												return;
											}

											callback();
										});
					},
					/**
					 * Returns json object received by iframe from server.
					 */
					_getIframeContentJSON : function(iframe) {
						// iframe.contentWindow.document - for IE<7
						var doc = iframe.contentDocument ? iframe.contentDocument
								: iframe.contentWindow.document, response;

						this.log("converting iframe's innerHTML to JSON");
						this.log("innerHTML = " + doc.body.innerHTML);

						try {
							response = eval("(" + doc.body.innerHTML + ")");
						} catch (err) {
							response = {};
						}

						return response;
					},
					/**
					 * Creates iframe with unique name
					 */
					_createIframe : function(id) {
						// We can't use following code as the name attribute
						// won't be properly registered in IE6, and new window
						// on form submit will open
						// var iframe = document.createElement('iframe');
						// iframe.setAttribute('name', id);

						var iframe = qq
								.toElement('<iframe src="javascript:false;" name="'
										+ id + '" />');
						// src="javascript:false;" removes ie6 prompt on https

						iframe.setAttribute('id', id);

						iframe.style.display = 'none';
						document.body.appendChild(iframe);

						return iframe;
					},
					/**
					 * Creates form, that will be submitted to iframe
					 */
					_createForm : function(iframe, params) {
						// We can't use the following code in IE6
						// var form = document.createElement('form');
						// form.setAttribute('method', 'post');
						// form.setAttribute('enctype', 'multipart/form-data');
						// Because in this case file won't be attached to request
						var form = qq
								.toElement('<form method="post" enctype="multipart/form-data"></form>');

						var queryString = qq.obj2url(params,
								this._options.action);

						form.setAttribute('action', queryString);
						form.setAttribute('target', iframe.name);
						form.style.display = 'none';
						document.body.appendChild(form);

						return form;
					}
				});

/**
 * Class for uploading files using xhr
 * @inherits qq.UploadHandlerAbstract
 */
qq.UploadHandlerXhr = function(o) {
	qq.UploadHandlerAbstract.apply(this, arguments);

	this._files = [];
	this._xhrs = [];

	// current loaded size in bytes for each file 
	this._loaded = [];
};

// static method
qq.UploadHandlerXhr.isSupported = function() {
	var input = document.createElement('input');
	input.type = 'file';

	return ('multiple' in input && typeof File != "undefined" && typeof (new XMLHttpRequest()).upload != "undefined");
};

// @inherits qq.UploadHandlerAbstract
qq.extend(qq.UploadHandlerXhr.prototype, qq.UploadHandlerAbstract.prototype)

qq
		.extend(
				qq.UploadHandlerXhr.prototype,
				{
					/**
					 * Adds file to the queue
					 * Returns id to use with upload, cancel
					 **/
					add : function(file) {
						if (!(file instanceof File)) {
							throw new Error(
									'Passed obj in not a File (in qq.UploadHandlerXhr)');
						}

						return this._files.push(file) - 1;
					},
					getName : function(id) {
						var file = this._files[id];
						// fix missing name in Safari 4
						return file.fileName != null ? file.fileName
								: file.name;
					},
					getSize : function(id) {
						var file = this._files[id];
						return file.fileSize != null ? file.fileSize
								: file.size;
					},
					/**
					 * Returns uploaded bytes for file identified by id 
					 */
					getLoaded : function(id) {
						return this._loaded[id] || 0;
					},
					/**
					 * Sends the file identified by id and additional query params to the server
					 * @param {Object} params name-value string pairs
					 */
					_upload : function(id, params) {
						var file = this._files[id], name = this.getName(id), size = this
								.getSize(id);

						this._loaded[id] = 0;

						var xhr = this._xhrs[id] = new XMLHttpRequest();
						var self = this;

						xhr.upload.onprogress = function(e) {
							if (e.lengthComputable) {
								self._loaded[id] = e.loaded;
								self._options.onProgress(id, name, e.loaded,
										e.total);
							}
						};

						xhr.onreadystatechange = function() {
							if (xhr.readyState == 4) {
								self._onComplete(id, xhr);
							}
						};

						// build query string
						params = params || {};
						params['qqfile'] = name;
						var queryString = qq.obj2url(params,
								this._options.action);

						xhr.open("POST", queryString, true);
						xhr.setRequestHeader("X-Requested-With",
								"XMLHttpRequest");
						xhr.setRequestHeader("X-File-Name",
								encodeURIComponent(name));
						xhr.setRequestHeader("Content-Type",
								"application/octet-stream");
						xhr.send(file);
					},
					_onComplete : function(id, xhr) {
						// the request was aborted/cancelled
						if (!this._files[id])
							return;

						var name = this.getName(id);
						var size = this.getSize(id);

						this._options.onProgress(id, name, size, size);

						if (xhr.status == 200) {
							this.log("xhr - server response received");
							this.log("responseText = " + xhr.responseText);

							var response;

							try {
								response = eval("(" + xhr.responseText + ")");
							} catch (err) {
								response = {};
							}

							this._options.onComplete(id, name, response);

						} else {
							this._options.onComplete(id, name, {});
						}

						this._files[id] = null;
						this._xhrs[id] = null;
						this._dequeue(id);
					},
					_cancel : function(id) {
						this._options.onCancel(id, this.getName(id));

						this._files[id] = null;

						if (this._xhrs[id]) {
							this._xhrs[id].abort();
							this._xhrs[id] = null;
						}
					}
				});